Radar level gauge systems are in wide use for measuring filling levels of tanks or containers. Radar level gauging is generally performed either as non-contact measurement wherein microwave energy is radiated towards a content of the tank, or as contact measurement wherein microwave energy is guided towards and into the content by a waveguiding probe.
This probe may be subjected to substantial forces due to movements in the content of the tank resulting from, for example, filling, emptying, stirring etc.
Furthermore, since radar level gauges frequently operate in environments with high pressure differences between an inside and an outside of a tank, a feed-through for sending signals between the inside and the outside of the tank should preferably be hermetically sealed.
In order to be able to use a radar level gauge system of the contact type over a wide temperature and/or pressure range, temperature stable and pressure-durable sealing materials are needed. Such materials, for example various types of glass and ceramics, are often brittle and may be damaged through forces acting on the probe.
In U.S. Pat. No. 6,019,007, a radar level gauge system of the contact type is disclosed, wherein sealing is provided through tightly pressing sealing materials between electrical and mechanical elements of the system. When forces act on the probe, these are thus directly transmitted to the scaling materials.
Since the above-mentioned type of sealing materials, typically various glasses and/or ceramics, generally are sensitive to other forces than compression, the sealing method disclosed in U.S. Pat. No. 6,019,007 would appear to practically prohibit use of these sealing materials.
There is thus a need for a more robust radar level gauging system, for example enabling the use of the above-mentioned type of sealing materials.